Browsing by Author "Wood, Robin"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Adjusting Mortality for Loss to Follow-Up: Analysis of Five ART Programmes in Sub-Saharan Africa
    (Public Library of Science, 2010-11-30) Brinkhof, Martin W. G.; Spycher, Ben D.; Yiannoutsos, Constantin; Weigel, Ralf; Wood, Robin; Messou, Eugène; Boulle, Andrew; Egger, Matthias; Sterne, Jonathan A. C.; Biostatistics, School of Public Health
    Evaluation of antiretroviral treatment (ART) programmes in sub-Saharan Africa is difficult because many patients are lost to follow-up. Outcomes in these patients are generally unknown but studies tracing patients have shown mortality to be high. We adjusted programme-level mortality in the first year of antiretroviral treatment (ART) for excess mortality in patients lost to follow-up. Methods and Findings Treatment-naïve patients starting combination ART in five programmes in Côte d'Ivoire, Kenya, Malawi and South Africa were eligible. Patients whose last visit was at least nine months before the closure of the database were considered lost to follow-up. We filled missing survival times in these patients by multiple imputation, using estimates of mortality from studies that traced patients lost to follow-up. Data were analyzed using Weibull models, adjusting for age, sex, ART regimen, CD4 cell count, clinical stage and treatment programme. A total of 15,915 HIV-infected patients (median CD4 cell count 110 cells/µL, median age 35 years, 68% female) were included; 1,001 (6.3%) were known to have died and 1,285 (14.3%) were lost to follow-up in the first year of ART. Crude estimates of mortality at one year ranged from 5.7% (95% CI 4.9–6.5%) to 10.9% (9.6–12.4%) across the five programmes. Estimated mortality hazard ratios comparing patients lost to follow-up with those remaining in care ranged from 6 to 23. Adjusted estimates based on these hazard ratios ranged from 10.2% (8.9–11.6%) to 16.9% (15.0–19.1%), with relative increases in mortality ranging from 27% to 73% across programmes. Conclusions Naïve survival analysis ignoring excess mortality in patients lost to follow-up may greatly underestimate overall mortality, and bias ART programme evaluations. Adjusted mortality estimates can be obtained based on excess mortality rates in patients lost to follow-up.
  • Thumbnail Image
    Item
    Point-of-care CD4 testing to inform selection of antiretroviral medications in south african antenatal clinics: a cost-effectiveness analysis
    (PLoS, 2015-03-10) Ciaranello, Andrea L.; Myer, Landon; Kelly, Kathleen; Christensen, Sarah; Daskilewicz, Kristen; Doherty, Katie; Bekker, Linda-Gail; Hou, Taige; Wood, Robin; Francke, Jordan A.; Wools-Kaloustian, Kara; Freedburg, Kenneth A.; Walensky, Rochelle P.; Department of Medicine, IU School of Medicine
    BACKGROUND: Many prevention of mother-to-child HIV transmission (PMTCT) programs currently prioritize antiretroviral therapy (ART) for women with advanced HIV. Point-of-care (POC) CD4 assays may expedite the selection of three-drug ART instead of zidovudine, but are costlier than traditional laboratory assays. METHODS: We used validated models of HIV infection to simulate pregnant, HIV-infected women (mean age 26 years, gestational age 26 weeks) in a general antenatal clinic in South Africa, and their infants. We examined two strategies for CD4 testing after HIV diagnosis: laboratory (test rate: 96%, result-return rate: 87%, cost: $14) and POC (test rate: 99%, result-return rate: 95%, cost: $26). We modeled South African PMTCT guidelines during the study period (WHO "Option A"): antenatal zidovudine (CD4 ≤350/μL) or ART (CD4>350/μL). Outcomes included MTCT risk at weaning (age 6 months), maternal and pediatric life expectancy (LE), maternal and pediatric lifetime healthcare costs (2013 USD), and cost-effectiveness ($/life-year saved). RESULTS: In the base case, laboratory led to projected MTCT risks of 5.7%, undiscounted pediatric LE of 53.2 years, and undiscounted PMTCT plus pediatric lifetime costs of $1,070/infant. POC led to lower modeled MTCT risk (5.3%), greater pediatric LE (53.4 years) and lower PMTCT plus pediatric lifetime costs ($1,040/infant). Maternal outcomes following laboratory were similar to POC (LE: 21.2 years; lifetime costs: $23,860/person). Compared to laboratory, POC improved clinical outcomes and reduced healthcare costs. CONCLUSIONS: In antenatal clinics implementing Option A, the higher initial cost of a one-time POC CD4 assay will be offset by cost-savings from prevention of pediatric HIV infection.
  • Thumbnail Image
    Item
    Virologic response of adolescents living with perinatally acquired HIV receiving antiretroviral therapy in the period of early adolescence (10-14 years) in South Africa
    (Wolters Kluwer, 2021) Nyakato, Patience; Schomaker, Michael; Sipambo, Nosisa; Technau, Karl-Günter; Fatti, Geoffrey; Rabie, Helena; Tanser, Frank; Eley, Brian; Euvrard, Jonathan; Wood, Robin; Tsondai, Priscilla R.; Yiannoutsos, Constantin T.; Cornell, Morna; Davies, Mary-Ann; Biostatistics and Health Data Science, Richard M. Fairbanks School of Public Health
    Background and objectives: Adolescents living with perinatally acquired HIV (ALPHIV) on antiretroviral therapy (ART) have been noted to have poorer adherence, retention and virologic control compared to adolescents with non-perinatally acquired HIV, children or adults. We aimed to describe and examine factors associated with longitudinal virologic response during early adolescence. Design: A retrospective cohort study. Methods: We included ALPHIV who initiated ART before age 9.5 years in South African cohorts of the International epidemiology Database to Evaluate AIDS-Southern Africa (IeDEA-SA) collaboration (2004-2016); with viral load (VL) values <400 copies/ml at age 10 years and at least one VL measurement after age 10 years. We used a log-linear quantile mixed model to assess factors associated with elevated (75th quantile) VLs. Results: We included 4396 ALPHIV, 50.7% were male, with median (interquartile range) age at ART start of 6.5 (4.5, 8.1) years. Of these, 74.9% were on a non-nucleoside reverse transcriptase inhibitor (NNRTI) at age 10 years. After adjusting for other patient characteristics, the 75th quantile VLs increased with increasing age being 3.13-fold (95% CI 2.66, 3.68) higher at age 14 versus age 10, were 3.25-fold (95% CI 2.81, 3.75) higher for patients on second-line protease-inhibitor and 1.81-fold for second-line NNRTI-based regimens (versus first-line NNRTI-based regimens). There was no difference by sex. Conclusions: As adolescents age between 10 and 14 years, they are increasingly likely to experience higher VL values, particularly if receiving second-line protease inhibitor or NNRTI-based regimens, which warrant adherence support interventions.